An X-ray diffractometer is known as one of apparatuses for analyzing crystallinity, crystal structures, etc. of samples.
FIG. 10 is a schematic diagram showing an exemplary arrangement of an X-ray optical system in a conventional X-ray diffractometer.
As shown in FIG. 10, the X-ray optical system is configured so that the surface of a sample S disposed on a sample stage is irradiated with X-rays generated in an X-ray source 10, and X-rays diffracted from the sample S are detected by an X-ray detector 20. As not shown in FIG. 10, the setting of an X-ray irradiation angle to the surface of the sample S and the movement of the X-ray detector 20 in a direction along which the X-rays diffracted from the sample S are captured are performed by operating a goniometer or the like.
The illustrated X-ray optical system is called as a Bragg-Brentano optical system in which a sample is irradiated with divergent X-rays 1 diverging radially from the X-ray source 10, and focusing X-rays 2 focused on one point are diffracted from the sample S.
The X-ray detector 20 is arranged at the focal point 2a (or a rear position approximate to the focal point) of the focusing X-rays 2 diffracted from the sample S.
A receiving slit 30 is arranged in front of an X-ray detection face 21 of the X-ray detector 20. The receiving slit 30 is an optical component for adjusting the cross-sectional area of X-rays to be guided to the X-ray detector 20 to adjust the resolution of the X-ray detector 20.
FIG. 11 is a schematic diagram showing an exemplary arrangement of the X-ray optical system in which an optical component called as a monochromator 40 on the optical path of the focusing X-rays 2 diffracted from the sample in the conventional X-ray diffractometer described above.
The focusing X-rays 2 diffracted from the sample S contain continuous X-rays having a wavelength distribution and plural characteristic X-rays. The monochromator 40 is an optical component having a function of extracting only X-rays having a specific wavelength (for example, Kα1 ray or Kα2 ray) from the focusing X-rays 2 to monochromate the focusing X-rays 2. The arrangement of the monochromator 40 on the optical path of the focusing X-rays 2 diffracted from the sample S makes it possible to remove noise components and detect only diffracted X-rays having a specific wavelength required for a sample analysis, so that the detection precision of the X-ray detector 20 (the detection precision of the diffraction angle) can be enhanced.
As shown in FIG. 11, the conventional X-ray diffractometer is configured so that the monochromator 40 is arranged behind the receiving slit 30, diffracted X-rays which focus at the focal point 2a and then diverge are made to enter the monochromator 40, and then monochromated diffracted X-rays are reflected. The diffracted X-rays which are reflected from the surface of the monochromator 40 focus at a second focal point 2c as focusing X-rays again. The X-ray detection face 21 of the X-ray detector 20 is arranged at the second focal point 2c (or a rear position approximate to the second focal point 2c).
For example, Patent Document 1 discloses a conventional X-ray diffractometer having this type of X-ray optical system.